This application claims the priority of German application 196 35 454.4 filed in Germany on Aug. 31, 1996, the disclosure of which is expressly incorporated by reference herein.
The invention relates to a constructional collector heat transfer unit having a refrigerant circulating system and to an air conditioner utilizing the heat transfer system. Heat transfer devices and refrigerant collector tanks, in the following called collectors, are known components of air conditioners having a refrigerant circulating system, as used, for example, in vehicles.
In German Published Patent Applications DE 43 19 293 A1 and DE 44 10 986 A1, constructional collector heat transfer units are described in the form of constructional collector heat transfer units for vehicle air conditioners in which a tube-shaped collector is arranged laterally on a condenser of a tube fin block construction and in this case is in a fluidity connection with an adjoining condenser collector tube. This known constructional collector condenser unit is intended for use in air conditioners in which the collector is positioned in the refrigerant circulating system on the high-pressure side behind the condenser.
On the other hand, air conditioners of the initially mentioned type are known in which the collector is arranged in the refrigerant circulating system on the low-pressure side behind the evaporator and a so-called interior heat transfer device is provided as an additional constructional unit by way of which the high-pressure side of the refrigerant circulating system between an air-cooled condenser and the expansion element is in a thermal contact with its low-pressure side between the collector and the compressor.
The invention is based on the technical problems of providing a new type of space-saving constructional collector heat transfer unit and an air conditioner equipped therewith which contains a collector arranged on the low-pressure side and an interior heat transfer device.
The invention solves these problems by providing a constructional collector heat transfer unit having a fluid-carrying heat transfer unit, and a collector for the intermediate storage of refrigerant, wherein the heat transfer unit is arranged in an interior space of a housing of the collector such that the fluid guided through the heat transfer unit comes in a thermal contact with the refrigerant through and intermediately stored in the collector, and wherein fluid connection lines for the heat transfer unit extend through the collector housing.
In the case of the constructional collector heat transfer unit, the fluid-carrying heat transfer device unit is arranged in the interior of the collector, that is, of the refrigerant collector tank, this unit being constructed and positioned such that the fluid guided through the heat transfer unit comes in a thermal contact with the refrigerant intermediately stored in the collector tank and removed from it. For the feeding and discharging of the fluid guided through the heat transfer device unit, corresponding connection lines are guided through the collector housing. In this manner, the constructional unit can be used for air conditioners in the case of which a heat transmission is to take place between the refrigerant which, after the intermediate storage in the collector, is to be transmitted and a fluid guided through the heat transfer unit, which fluid may in particular be the same refrigerant in a different section of the refrigerant circulating system but does not have to be that refrigerant.
In the case of certain preferred embodiments of a constructional collector heat transfer unit, the heat transfer unit is implemented by a tube construction with at least one flat-tube spiral having mutually spaced turns. The flat-tube spiral is inserted and axially covered in the collector housing such that the spiral space formed by the spaced flat-tube turns forms a spiral flow duct for the refrigerant removed from the collector. In this manner, the withdrawn refrigerant is in a thermal contact along the spiral turn path with the fluid guided in the interior of the flat tubes of the heat transfer unit.
In certain preferred embodiments, the heat transfer unit of the constructional collector heat transfer unit contains two flat-tube spirals which are arranged axially side-by-side separated by an intermediate bottom, these flat tube spirals being in a fluidity connection with one another by means of their two radially exterior ends or by means of their two radially interior spiral ends by way of a connection tube extending through the intermediate bottom. According to the selection of the connections, the flat-tube spirals may be fluidically connected in series or in parallel. Analogously, the two pertaining spiral-shaped flow ducts are connected by way of a connection opening in the intermediate bottom on mutually corresponding radial end areas and in this case, depending on the system design, are connected in series or in parallel.
The air conditioners according to preferred embodiments which are equipped with a constructional collector heat transfer unit whose collector on the low-pressure side is arranged in the refrigerant circulating system behind an evaporator, while the heat transfer unit operates as a so-called interior heat exchange device which is used for the heat transmission between the high-pressure and low-pressure side of the refrigerant circulating system. As a result, a compact construction of the air conditioner, particularly of the system part concerning the collector and the interior heat transfer device can be implemented. In comparison to conventional systems of this type with a constructional unit of the interior heat transfer device separated from the collector, the connection line which is required there is saved in addition to the connection points between the collector and the interior heat transfer device.
It was found that the inserting of such an interior heat transfer device, which causes a further cooling of the refrigerant on the high-pressure side behind the condenser connected with an overheating of the refrigerant taken in by the compressor on the low-pressure side, for certain air conditioners and refrigerants, permits an improvement of the refrigerating capacity and of the refrigerating capacity rate. In the case of air conditioners used for air-conditioning vehicles, the interior heat transfer device can also protect the compressor from damage caused by refrigerant taken in a liquid state.
In the case of a further development of preferred embodiments of an air conditioner, the interior heat transfer device on the low-pressure side is situated in the outlet-side flow path of the collector and can therefore cause, for example, an overheating of the refrigerant withdrawn from the collecting space.
Other objects, advantages and novel features of the present invention will become apparent from the following detailed description of the invention when considered in conjunction with the accompanying drawings.